/Engine/Plugins/Experimental/Fracture/Source/FractureEngine/Public/FractureEngineClustering.h
Cluster the chosen transform indices (and update the selection array to remove any that were not clustered, i.e. invalid or root transforms)
true if the GeometryCollection was updated
static bool ClusterSelected ( [FGeometryCollection](API\Runtime\Chaos\GeometryCollection\FGeometryCollection) & GeometryCollection, [TArray](API\Runtime\Core\Containers\TArray)< int32 > & InOutSelection )